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Allow unaligned load/store in QVM interpreter/x86 compiler

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constructions like (dataMask & ~3) was used to protect against out-of-bound load/store when address is 4-byte closer to dataMask
 but at the same time it effectively cut low address bits for ALL load/store operations which is totally wrong in terms of conformance to ALLOWED (i.e. generated by q3lcc from C sources) low-level operations like packed binary data parsing
This commit is contained in:
ec- 2017-03-15 11:42:58 +02:00 • committed by Tim Angus
parent abce15055c
commit 566fb0edfc
4 changed files with 17 additions and 14 deletions
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8
code/qcommon/vm.c
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@ -451,13 +451,15 @@ vmHeader_t *VM_LoadQVM( vm_t *vm, qboolean alloc, qboolean unpure)
if(alloc)
{
// allocate zero filled space for initialized and uninitialized data
vm->dataBase = Hunk_Alloc(dataLength, h_high);
// leave some space beyound data mask so we can secure all mask operations
vm->dataAlloc = dataLength + 4;
vm->dataBase = Hunk_Alloc(vm->dataAlloc, h_high);
vm->dataMask = dataLength - 1;
}
else
{
// clear the data, but make sure we're not clearing more than allocated
if(vm->dataMask + 1 != dataLength)
if(vm->dataAlloc != dataLength + 4)
{
VM_Free(vm);
FS_FreeFile(header.v);
@ -467,7 +469,7 @@ vmHeader_t *VM_LoadQVM( vm_t *vm, qboolean alloc, qboolean unpure)
return NULL;
}
Com_Memset(vm->dataBase, 0, dataLength);
Com_Memset(vm->dataBase, 0, vm->dataAlloc);
}
// copy the intialized data